The invention relates to a fuel tank cap at the filler neck of a motor vehicle fuel tank, with a locking gas cap, which can be swiveled about a pivoting axis and a locking part, which is disposed internally at the locking gas cap and lies against the edge of the filler neck, sealing it, in the closed position, in which it can be locked and in which the locking gas cap is spring-loaded in the opening direction, it being possible to unlock the locking gas cap and swivel it into the open position by pressing down on it briefly especially by means of a robot-guided fuel pump nozzle.
For conventional fuel tank cap systems, a filler neck, starting out from a fuel tank, is manually closed off tightly by means of a screw-in locking gas cap. The locking gas cap, in turn, is covered by a fuel tank flap, which is embedded in the side wall of the vehicle. However, such fuel tank cap systems are obviously not suitable for the automatic refueling of motor vehicles which is planned for the future.
A series of differently configured fuel tank cap systems has already been proposed in order to make automatic refueling possible. For example, the Offenlegungsschrift DE 42 43 883 A1, which is incorporated herein by reference, already discloses a locking construction of the type described above. The unlocking takes place due to the fact that an unlocking pipe, which can be connected with the refueling pipe, comes up against a lever arm of the locking gas cap, opening the latter. This means, that in every case, aside from a fuel pump nozzle, a separate unlocking pipe must be provided, since the lid remains open only as long as the unlocking pipe is pressed onto the lever at the locking gas cap. In turn, such design requires that special refueling equipment is required and that it is not possible to use different automated fueling systems in conjunction with such a motor vehicle closing device.
However, since it is absolutely essential to construct the fuel tank cap in such a manner that different automatic refueling systems can also be used in conjunction with such a fuel tank cap, insofar as it cannot be expected that the oil industry will introduce a uniform refueling system, it is therefore an object of the present invention to configure a closing device at the filler neck of a motor vehicle fuel tank of the type referred to above, in such a manner that it can be unlocked from the outside merely by briefly pushing against it and, in the same way, closed and locked once again so as to form a seal simply by pressing it shut.